I have a few MP3 podcasts that I transfered from my PC ostensibly to the Podcast folder on my Sansa Fuze ClipZip. Unfortunately, when I try to access through the player, the files show up under the Music section and not the in the Books/Podcast section. That means the podcasts don’t automatically book mark.
I believe you have to make sure the Genre field in the ID3 tag indicates Podcast. MP3Tag is the most popular, free, dedicated tagging program.
If I recall correctly, podcasts and audiobooks put into those folders are supposed to process themselves automatically without the need for the genre field to be filled in. But if that’s not happening, best to fill in the ID3 genre field appropriately (if not yet done), to see if that does the trick.